问题描述
create table b as
select * from table a;
请添加检查条件
- 如果表 a 有记录,则应创建表 b
- 如果表 a 没有记录,则不应创建表 b
解决方法
您可以有条件地使脚本失败
--this will generate HiveException with message ASSERT_TRUE(): assertion failed
--it the table is empty and the script will exit
select assert_true(count(*)>0) from a;
--If previous statement executed successfully
create table b as
select * from table a;
另一种方法是使用 java_method("java.lang.System","exit",1)
:
select "Checking source is not empty ...";
select java_method("java.lang.System",1) --Exit
from
(
select count(*) cnt
from a
)s where cnt=0; --select only if count=0
select "Creating the table b ...";
--Put create table here